Magnetic sheet classifier



Bea, H, 1942. H. a. CUMMINGS ETAL MAGNETIC SHEET CLASSIFIEI I Filed June 4, 1937 4 Sheets-Sheet 1 INVENTORS Dec. 1, 39542. H. B. CUMMINGS ETAL 23@3,5Z5

MAGNETIC SHEET CLASSIFIER Filed June 4, 1937 4 Sheets-Sheet 2 w 1942- H. B. CUMMINGS EI'AL 3 MAGNETIC SHEET CLASSIFIER Filed June 4,- 1957 4 Sheets-Sheet 5 Nf/NTORSII A %m /A A? Cit/MM. M 9 Gimp,

Dec, 1, 1942.

H. B. CUMMINGS ETAL 23%,526

MAGNETICSHEET CLASSIFIER Filed June 4, 1937 4 sheets -sheet 4 H I .T/

i l L Patented Dec. 1, 1942 MAGNETIC SHEET CLASSIFIER.

Howard B. Cummings and George R. Carroll, Aliquippa, Pa., assignors to Jones & Laughlin steel Corporation, a corporation of Pennsylvania Application June 4, 1937, Serial No. 146,341

25 Claims.

"-Our present invention relates to the handling of ferrous metal strip and sheets and more particularly to a method and apparatus for classifying or sorting ferrous metal sheets as they are sheared from strip in accordance with their strip gauge characteristics.

As set forth in an application filed by Geor e A. Kaufman'on November 12, 1934, Serial No;

752,792, the classifying or sorting of metal sheets has been a diillcult problem to solve satisfactorily. It has been customary in the past to classify these sheets after they are sheared from a strip or other piece of material. As a result, the most common method of classification, i. e., in accordance with gauge or weight, has been a manual procedure which is relatively slow, expensive and inaccurate. For a long time the industry has been seeking to mechanize this work or to reduce the amount of manual labor required, thus releasing these men-for more important work. Insofar as already sheared sheets are concerned, certain proposals have in the past been made to classify such by methods involving suction cups for picking up the individual sheets, or in other similar ways mentioned in the application already referred to. Practically no effort has been made, aside from the apparatus and procedure set forth in said Kaufman application,

to determine the gauge or weight characteristics of the material while still in the form of strip and then subsequently to shear the strip into sheets and to classify the sheets in accordance. with their strip gauge characteristics. A rapid, accurate method and apparatus for the classification of ferrous sheets in such manner as to minimize or eliminate manual operations is very much desired in this field, particularly one which will handle sheets at the exceptionally rapid rate of 600-700 per minute, depending on their. length, without marring or damaging the sheets in any way. Insofar as we know, there hasbeen no satisfactory method or apparatus proposed to take care of this situation.

It is, accordingly. one of the objects of our present invention to classifyv ferrous metal sheets .40

It is another object of our invention to provide a system of classification for ferrous metal sheets so that such sheets as have desired or permissible characteristics can be magnetically separated from the remainder of the sheets which are defective or deficient in any respect. Another object of our invention resides in a 5 system of conveyors which is so constructed and arranged that as a stream of just sheared sheets passes into the conveyor system certain sheets can be diverted from the stream of sheets in accordance with certain characteristics thereof as determined while still in the form of strip.

A further object of our invention resides in feeding a strip of metal past a station where the characteristics thereof are determined, in shearing the strip into sheets, in receiving the sheets on a conveyor system which has at least two possible paths of travel for such sheets and in magnetically diverting certain of said sheets from such stream 01' sheets, thus discharging the sheets at separate points as separate groups, piles or 2 stacks.

A further object of our invention resides in the provision of a magnetic conveyor which is capable of picking up predetermined sheets from I a stream of sheets .to deliver the same to a separate point of discharge as well as in the correlation thereof with the gauge or other means for determining the characteristics of the strip from which the sheets are formed by shearing 30. prior to the shearing operation.

magnetically segregating ferrous metal sheets, conveying them while magnetically holding them and causing them to be deposited at a predetermined point or in accordance with a predeter mined sorting or classifying scheme.

Still further objects reside in such various details, combinations and sub-combinations of structural and procedural features as are here- ,,inafter set forth. v

40 Other and further objects and advantages will either be understood by those skilled in this art or will be apparent or pointed out hereinafter.

In the accompanying drawings: Figure 1 is a side elevational view of part of hereinabove set forth;

Fig. 2 is a continuation of Fig. 1 and illustrates the rear or feed end of the apparatus; 1

Fig. 3 is a plan view of a portion of the apparatus shown inFigs'. 1 and 2;

Fig. 4 is a schematic or diagrammatic illustration of the present apparatus and procedure and shows the paths of travel of sheets there- A still further object of our invention lies in an apparatus embodying the present invention which will secure the objects and advantages Fig. 8 represents a schematic wiring diagram.

of the electrical and magnetic control system.

Similar numerals designate corresponding partsthroughout the various views of the draw- 4 ings.

Referring first to our invention in a general manner, we point out that it involves the determination of the gauge or other desired characteristic of the metal while it is still in the form of a strip. A strip of material such as a coil of tin plate is fed in the usual way to a flying shear through suitable feed rollers and at a suitable point prior to shearing the strip into sheets the characteristics of the strip are determined. Insofar as the actual gauge or thickness of the material is involved, this can be continuously measured or indicated by the use of any suitable gauging device such as a Pratt and Whitney Electro-limit gauge as disclosed in the aforementioned Kaufman application, the construction, operation and electrical circuits of which are hereby made a part of this disclosure. Insofar as surface or other defects in the strip are concerned these are observed by an operator or inspector stationed at or near the gauge. In some cases, the strip has wavy edges or other defects which are not accurately gaugeable and the operator or inspector also notes (and usually marks) such. The strip may be stopped for marking purposes, if desired. As the strip passes through the gauge, the off-gauge characteristics, beyond tolerance limits, are impressed on electrical circuits precisely as set forth in the Kaufman application mentioned. The strip is next sheared into sheets by means ofthe flying shear and the sheets are then received on a belt or conveyor which transfers them to the classifier. For the purposes of the present invention, the sheets are segregated into two groups, one of which will be hereinafter termed O. K." sheets and the other of which wlll'be termed ,otf-gauge" sheets, with the understanding that prevent such sheets from following the normal or "O. K." path of travel through the classifier. The same is true of strip noted or marked as off-gauge bythe operator or inspector, there being a manual electrical parallel control actuatable by him for causing such material also to follow the off-gauge path of travel. Thus this control which is in addition to and parallel with the gauge control is a manual control and consists primarily in shutting off the power or magnetizing force (as by pushing a button or switch) which is imparted to one of the conveyors of the classifier or a part thereof, hereinafter called the magnetic conveyor, so that on-gauge" sheets are not attracted by the magnetic conveyor and hence follow a different path of travel through the classifier than "0. K. sheets. In other words, our invention involves magnetically attracting "0. K." sheets while preventing oi!- gauge sheets from being magnetically attracted and thence causing each group to follow a different path of travel and to be discharged at a separate point. At each point of discharge a suitable piler is provided which produces a uniform stack of sheets at that point; however, the piler for the "O. K. sheets may be so constructed as to effect stagger piling in accordance with the aforesaid Kaufman application. Such stagger piling is deemed to be a feature of the present invention and stagger piling as per said Kaufman application is hereby made a part of this disclosure.

Referring now to the drawings, a suitable framework is provided designated as a whole by the numeral 10. This framework is made up of vertically spaced beams or supports II and horizontal beams I! which are suitably bolted or otherwise secured together, as shown at the angle bars l3. Any necessary braces, etc., ll may be provided for the usual purposes. In general, the classification and piling takes place within the framework III; the motive power and driving mechanism are disposed on the top of the framework for which purpose a suitable platform or support I! is erected. It is believed that it will be most convenient to describe the apparatus beginning from the right-hand part of Fig. 2 and proceeding to the left-hand portion of Fig. 1 since this follows the course of the material during operation of the classifier and in describing the apparatus in this way, we will at the same guingiejollow the schematic illustration shown in The strip of tin plate or other ferrous metal or alloy is fed from a coil over suitable tables and emerges through feed rolls I6. From feed rolls I 6 the strip passes through a gauging mechanism, such as the electro-limit gauge already referred to, which is designated diagrammatically by the numeral l'l. As the strip passes through the gauge 1'! oil-gaugev characteristics, beyond tolerance limits, are impressed upon the gauge circuits and effect the control hereinafter explained. The operator or inspector also utilizes his parallel manual control as tostrip portions having ungaugeable or surface or other defects which will not cause the effecting of automatic control by the gauge. From gauge H the strip is fed by pinch rolls I 1a tothe shears indicated at [8 and is there cut transversely into sheets of the desired length. The construction and operation of flying shears is well known in this art and per se forms no part of the present invention. We, however, point out that the speed or frequency of the shears is particularly related to the speed of the strip in accordance with known practice so as not only to produce sheared sheets of the desired length but to produce such sh'eets of equal lengths. In practice, the length of the sheet is determined by appropriately adjusting the speed or frequency of the shears and the strip is thus sheared while it is still moving at a considerable rate of speed since the operation of a flying shear does not necessitate the stopping of the strip for shearing purposes. Consequently, the sheets are discharged from the shear with an appreciable linear velocity and hence they pass onto the first conveyor l9, two such sheets being indicated by the numeral 20.

This conveyor I9 is operated at any suitable speed up to approximately 700 feet per minute and as will be apparent from Figs.2 and 4 the sheared sheets are thus conveyed along conveyor l9 until they come within the influence of the magnetic conveyor indicated as a whole by the numeral 2| operating at the same speed. The details of the magnetic conveyor are shown in Figs. to 7, inclusive, and will be hereinafter referred to. When the sheets reach a point adjacent the end of conveyor 19 it will be apparent that there are two possible paths of travel thereafter. If the adjacent portion of the magnetic conveyor 2| is energizedthen the sheets will be magnetically picked up from conveyor l9 and conveyed along the under side of the magnetic conveyor (as sheet 22) until they reach a point near the upper (higher) end thereof. When these magnetically attracted sheets tend to project from the end of the magnetic conveyor,'the magnetic field gradually becomes insufllcient to hold the sheets due to the loss of contactof the conveyor with the sheets and the passage of the sheets beyond the full force of the magnetic field; eventually the sheets fall therefrom, as is indicated by the sheet 23 in Figure 4. As sheets reach such position and fall from the'magnetic conveyor, they are received by the conveyor 24 which conveys them- (at 70-350 linear feet per minute) (as sheet 25) to a stack or pile designated by the numeral 26 (see Fig. 4). Sheets which are permittedor caused to follow the just mentioned path oftravel are the O. K." sheets; the sheets which are of proper gauge within desired tolerance limits and-which have no observable surface or other defects which would cause them to be rejected or diverted by the gauging device or by the operator or inspector.

When sheets whichare off-gauge; .as already defined, reach a position, as above explained,

with our present invention with practically 100% (at least 98-99% accuracy at a rate as rapid as,

600-700 sheets per minute, depending on their length. Material exhibiting surface defects is caused to travel to the off-gauge pile as already indicated. 1

While the motive and driving means illustrated in Figs. 1 and 3 of the drawings need only be such as will enable us to carry out theobjects gineering judgment or development. The motive and driving means are suitably mounted atop the framework Hi. The numeral 35 designates a H. P.) motor provided with a brake and designed to rotate at 69 R. P. M. This motor 35 has.

a shaft 36 provided with suitable couplings 31. The shaft 36 is also provided with worm gear 38 meshing with gear 39, the two gears having a reduction ratio of :1.

bearings 4| suitably mounted upon. the framework i0. This shaft is provided at its ends with the sprockets 42. Beyond the couplings 31 is an-.

other set of reducing gears and another transverse shaft thesame as those already described designated by the numerals 43, the purpose of where they would normally be attracted magor pulleys is provided to, which are connected the belts or drives 5|, 52, 53 for driving the various conveyors at definite or related speeds as.

cause attraction. By referring to Fig. 4 it will be observed that the magnetic conveyor 2i is elec;

trically or: magnetically divided into two sets of coils Aand B." It is the A coils which are de-ener'gized to prevent the attraction of offgauge sheets, this being more fully explained in connection with the description of Fig. 8. In such case, the sheets then fall off conveyor i9, as illustrated by the sheet 21 in Fig. 4, and are received by the conveyor '28 therebelow (operating at -350 linear feet per-minutei'and thus are con-' veyed- (as sheet 29') to another or separatepile 3 1 verse shafts '55 which rotate. in bearings -50.

30 (see Fig. 4)} As already explained, piling in I either'instancemay be either such that the sheets are uniformly-piled in vertical alignment or are laterally stagger-piled; In-fthis way. sheets are; classified either as O; -K." or oif gaugfl sheets as they are sheared from strip but'in accordance with their-characteristics as determined while" still. in the'form of strip. Thus no gauging or other operations need'becarried out upon the sheared sheets themselves which represents a marked advantage'inthis field as there is no l-ability of damaging the sheets. Likewise, the

sheets can be classified at an exceptionally rapid rate limited only by the speed of the shear. We have, for example, classified sheets in accordance which will be hereinafter set forth.-

Located between the two transverse shafts 40 is a 5 'H. P. motor 44 capable of producing 750 R. P. M. The shaft 45 extending. therefrom is provided with acoupling 46 and is connected to a speed reducer 41" whichhas a ratio of 4%:1. Fromthis gear reducer. extends a shaft 48 which is provided withan-end bearing supported on- I the framework it and intermediate the gear reducer' and'the bearing a number of sprockets hereaiterset forth.v The numeral 54 designates al H. P. electric motor of R. P. M. provided with a' brake I and which has substantially the same relation-.-

ship with the transverse shafts 55 as motor 35' has 'with the previously referred Zto transverse shafts 40. Motor 54 has a-shaft 56 having con-- plings 51 therein, the shaft being provided with gears 58 meshing with wormgears 53 oriutransmounted pn'the framework- I0. and whichare provided with $prockets'6lat theirends for receiVing-ch'ainsti'. whichin -turn serve toraise and" lower the: O. K. pller'mechanism as i hefiexible chains 43 are connected at their lower ends to a framework 62 which servesas a support forthe off-gauge piler designated as a whole by the numeral 63. This framework'fl can thus-- Ice-raised or lowered as required and such action, is accomplished through the rotation of the sprockets 42 on transverse shafts, the rotation being'obtained through operation of thezreducing gears actuated :by the motor 35. v This raising and lowering of the framework makes it pos- The gear 39. is secured on transverse shaft 40 mounted'for rotation in will be ""hereinafter more fullyset forth.. f -As will be understood-fromFigiire 1 especially,

ited arc, is connected with sibie to accommodate the desired number of sheets on the off-gauge 'pilevand also serves to maintain the top of the pile in proper relation to subsequently received sheets in order to producethe desired results such as to insure a maximum upon said beam or framework are guides which serve to form a properly aligned stack of sheets.

These guides may consist of side guides 4 andend guide 65.

In similar manner the lower ends of flexible chains 2 are connected the framework II which forms a support for the O. K. piler mechanism designated 'as a whole by the numeral 81. Both chains is and chains 42 are connected to their respective frameworks by any suitable means such as the bolt assemblies indicated by the numeral I, and, like chains 43, chains 82 are actuated through the sprockets I of transverse shafts II. the source of power being motor 54 and thus enabling the O. K. piler to be raised or lowered as required.

Between the end of conveyor 28 and this piler 83, a pair of pinch rolls is located, indicated at as, and these rolls may be adjusted toward and from each other by the take-up or. adjusting mechanism indicated at II which substantially comprises a block II within which the lower pinch roll may be adjusted upwardly or downwardly and the position of which is varied-or adjusted by means of take-up screw I2 acting through spring 13. A yoke 14 is provided at this point in the usual manner.

As will be apparent from Figs 1 and 3, the conveyor 28 is driven through a gear or pulley l5 actuated by the belt 52 (Fig. l) the other end of which passes around a pulley provided on shaft 48 (Fig. 3), already described. .The magnetic conveyor 2| is driven by belt II which passes around a pulley on said shaft 48. Likewise, conveyor 24 is driven similarly to conveyor 28, through pulley l6 and belt 53 which passes around a pulley on said shaft 48. In this manner. only one source of power is used to drive all three of the conveyors which carry out the classification and by. proper selection of pulley sizes the desired relationship between the speeds of these conveyors is readily achieved. This also prevents piling up of sheets on any of theoonveyors and prevents jamming at the pinch rolls where the sheets are fed from the. conveyors to the pilers in which connectionthe piler 01 which receives the 0. K. sheets may be constructed su like that of the piler 63 already described for off-- gauge sheets. w

In the piler for 0. K. sheets, howeven -we have more or less diagrammatically-illustrated a stagger piler whichis constructed in accordance with that illustrated and described in the I cordance with their characteristics. Resting core referred to and pulls down link ll thus imparting rotational movement to shaft II and advancing the mechanical fingers mentioned. These details are mentioned for the sake of completeness but are not per se a part of the present invention. For a full description and illustration thereof, we refer to the said Kaufman application. Likewise, a set of pinch rolls II is provided between the end of conveyor 24 and the piler 81 and-one of the pinch rolls, in this case the upper one, is adapted to be adjusted for the usual purposes as explained anent pinch rolls II. The upper pinch roll is movable in block .2, adjustment being effected by turning bolt II which varies the tension of spring 84, the whole being supported by yoke l. Pinch rolls ll and II not only function as feed rolls for the pilers l3 and ll but, the construction of such causes the sheets to be discharged to the pilers in slightly bowed condition. This condition has been found to be high y advantageous for reasons which will be understood byreference to the above-identified Kaufman application.

Referring now to the details of construction of the magnetic conveyor 2| illustrated in Figs. 5 to 7, inclusive, end brackets II are mounted on the main framework il in any suitable manner to maintain the illustrated positioning thereof. These end brackets 85 are mechanically connected by the longitudinal metal shoes it which are suitably secured at their ends to said brackets by rivets, bolts or the like 81. Extending away from each end bracket is a pair of bearing supports 8! in which rolls II are suitably iournaled. These rolls carry-the conveying belt a which is made of rubber. but which may be made of any suitable flexible material. One of these rolls such as that at the left of Fig. 5 is suitably driven as by belt II herein referred to in connection with the general description of the apparatus.

It will be noted that the longitudinal metal shoes 86 are in parallel spaced relationship and that additional longitudinal shoes ii are also diaposed in parallel spaced relationship so that the shoes ll alternate with the shoes sl. Extending transversely of the magnetic conveyor and hence at right angles to the shoes just referred to are a plurality of parallelspaced metal tie bars 92. These tie bars are also vertically spaced 4 with respect to the longitudinal shoes and II. the relationship being clearfrom Fig. '7 particularly. It will be further noted that both the longitudinal steel shoes and the trans- '55 verse tie bars 'are provided with apertures which register. when these elements are assembled as j shown. Between the longitudinalshoes and the tie bar's a'plurality of magnetic coils I! are disand'these are insulated from the steel shoes and the tie bars by the non-metallic washera 04 which may be,'forinstance, of Bakelite v v or any other suitable material. These magnetic aforementioned Kaufman application Serial No.

752,792. The plate 'll coils are hollow, that is, they have a central opening .therethro'ug'h for the reception of the ll there shown, which is rotatable through a limwithin a solenoid casing It. There are also suitable mechanical fingers provided (not shown),

a core'inot visible) 7 which are advanced or retracted'in accordance with the condition of the solenoid, i. e., whether 7 it is energized or de-energized. For example,

when the solenoid is energized coreseach of which'consists of a central portion st and end portions I oi! smaller-diarrieter, both the central portions and the endportions being of circular cross section. Therespective end portions st of the'eores ll arereeeived in and secured ,to the. steel shoes. andthe tie bars 2., The connection with-the steel shoes may be made by riveting or other suitable means indicated by the configuration thereof and the p 0 connection with the tie bars made by suitable it attracts the 7s nuts 81.

It will be still further noted, that whereas there are seven rows of cores thereareonly three rows up to the maximum number (7) of parallelshoes.

We have found, however, that for the present purpose three rows of coils are ample to produce a sufllciently strong'magnetic field. The magnet belt may also be simplified by providing only three longitudinal shoes all of which'have rows of magnetic coils. The utilization of a rubfield or flux in the conveyor is always of sufficient value as to the upper portion of the conveyor .to magnetically hold sheets which have previously been attracted from conveyor l9 by the lower portion of the magnetic conveyor when the "A" group of coils is energized, nevertheless when the "A" her or rubberized belt has no serious insulating effect in that it does not prevent the desired attraction of the sheets. While we have not shown the power connections in detail, these have been diagrammatically illustrated in Fig. 8 and will be readily understood by those familiar with'magnetic fields and the construction and use of magnetic coils. The connections will of course vary depending upon whether the source of current is A. C. or D. 0., although D. C. is preferred as the source of energy because it simplifies the installation.

In Fig. 8, conductors L1 and L2 are connected to a suitable source of D. C. current supply. A

' contact making micro-ammeter 98 is connected across the conductors L1 and L2, this microammeter being the same as disclosed in said Kaufman application, the construction, circuits and details of which are hereby made a part hereof. A suitable coil 09 is provided, as shown in the micro-ammet-er connections for a purposeto be explained.

As will be understood, micro-ammeter 98 is provided with the contacts I00 and IN, the former being for control of over-gauge material and the latter being for control of under-gauge material. by means of a pivoted pointer I02. When overgauge material, beyond the upper tolerance limit, is passing through gauge |1,'pointer I02 moves to the right and makes connection with contact I00.

Similarly, when material is passing through gauge I'I which is below the lower tolerance limit, pointer I02 moves to the left and makes connection with contact WI. The actuation of pointer I02 is effected through the coil I03 which forms a part of the gauge circuit.

Also connected across conductors L1 and L2 are the magnetic coils 93 which are electrically divided into two groups as shown.- Group A corresponds to the lower group of coils 93, as shown in Fig. 4, and group "3 corresponds to the upper group of coils 93, as shown in that figure. The connections for the group Al cells 93 are provided with a normally closed contactor indicated by the numeral I04, coil 99 being associated therewith for control purposes. Thus when off-gauge material beyond tolerance limits is passing through gauge I1 and hence when pointer I02 makes connection with either contact I00 or contact I0 I, coil 99 becomes energized and causes normally closed contactor I04 to open, thus breaking the circuit of the group A" set of coils 93. As a result, the lower portion of magnetic conveyor 2| The actuation and control is efiected is de-energized but the coils constituting group B remain always energized when the apparatus is in use or operation. While the construction of magnetic conveyor 2| is such that the magnetic group is deenergized there is no'interference with the normal functioning of the "3 group of coils. At the same time, however, the magnetic field or flux in the lower portion of the magnetic conveyor 2| is reduced to a value insufiicient-to attract sheets to the conveyor I9 and hence such sheets remain thereon and pass to conveyor 28 and thence to the off-gauge piler.

It will, therefore, be'understood that when offgauge material, as hereinabove defined, is passing through gauge I1 and/or when the operator or inspector wishes to divert certain portions of strip in the form of sheets to the off-gauge pile, the electrical connections and functions are such that when this strip material in the form of sheets reaches the lower end of magnetic conveyor 2|, the A group of coils is deenergized thus causing such sheets to be conveyed to the off-gauge piler. The other or O. K. sheets which are formed from strip material of satisfactory gauge and surface characteristics cause no actuation of micro-ammeter 98 and hence no de-energization of .the A group of coils, and hence such sheets in their sheared form when they reach the lower end of magnetic conveyor 2| are magnetically attracted and carried along for discharge to the O. K." piler, as already explained. It is pointedv out that in connection with the gauge and micro-ammeter and their construction, circuits and operation are basically the same as described and illustrated in the aforesaid Kaufman application and hence are not repeated here, reference being had to such application for such details;

The above is intended more as illustrative than limitative and we do not intend to restrict ourselves to the precise details shown and described. We may make such variations, omissions, substitutions and additions as will be suitable and proper for various installations, and all such changes are to be considered a part of the present invention so long as they come within the scope and principles herein set forth. Rather our invention is to be measured by the subjoined claims. One such variation is that, if desired or preferred.

elf-gauge sheets may be magnetically attracted instead of O. K. sheets. Also, the invention is not limited to the sorting or classification of tinplatesheets but may be used for sheets of any ferrous metal or alloy or other material capable,

which connection sheets may be magnetically held by a conveyor and dropped therefrom at suitable points in accordance with their characteristics in a predetermined time-delay-controlled manner. Other uses will suggest themselves to those skilled in this art.

Having thus described our invention, what we claim as new and desire to secure by Letters Patan "O. K. group and an ofl-gauge group as they are sheared from strip which comprises feeding such strip, determining the thickness characteristics thereof, shearing it into sheets, magnetically attracting "O. K." sheets and conveying them to a point of discharge and conveying offgauge sheets to a separate point of discharge.

2. A method of classifying metal sheets into "0. K." sheets and off-gauge sheets as they are sheared from strip comprising feeding the strip to a shear, determining the thickness characteristics of the strip before it reaches the shear, shearing the strip into sheets and, in accordance with the strip thickness characteristic determinations, magnetically segregating "O. K." sheets from off-gauge sheets.

3. A method of. classifying metal sheets as they are sheared from strip comprising feeding the strip to a shear, determining the thickness characteristics of the stripbefore it reaches the shear,

shearing the strip into sheets and conveying the sheets to points of discharge in accordance with the characteristics thereof as determined while in strip form, 0. K. sheets being magnetically diverted from off-gauge sheets.

4. A process of classifying metal sheets as they are sheared from a metal strip comprising feeding such a strip, continuously determining. the thickness and surface characteristics of such strip, shearing the strip into sheets of substantially equal length, conveying all the sheets to a classifying apparatus and thereafter separatin the sheets into two roups by magnetically attracting those sheets which form one of said groups and then conveying the thus magnetically separated sheets to a separate point of discharge.

5. A method of classifying metal sheets into "0. K." sheets and off-gauge sheets as they are sheared from strip and without carrying out any operations upon the sheared sheets themselves which comprises determining the thickness characteristics of the strip material prior to its severance into sheets, shearing it into sheets of substantially equal length, conveying all sheets to a zone where they are subjected to the influence of a magnetic field normally of sufficient strength to attract them, so controlling the magnetic field that only "0. K." sheets are magnetically attracted and separately conveying the thus attracted sheets and the unattracted sheets to separate points of discharge.

6. A method of classifying metal sheets in accordance with their thickness characteristics while still in strip form prior to severance into sheets comprising calli'pering the strip while feeding it, forming sheets therefrom, conveying all the sheets to a common zone and subjecting only sheets'which form one classification to the influence of a magnetic field of suflicient strength to cause physical displacement of such sheets and then conveying diverted and undiverted sheets to separate points of discharge and predeterminedly piling or stacking them at such points.

7. A process of classifying metal sheets into an "O. K." group and an off-gauge group in accordance with their strip characteristics prior cated as "O. K. sheets, the balance of the sheets being segregated from "O. K." sheets.

9. A method of handling material which is first in strip and then in sheet form which comprises feeding a strip of such material, causing off-gauge strip variations beyond predetermined tolerance limits to be impressed upon electrical circuits, shearing the strip into'sheets, conveying all of said sheets within the influence of a mag-' netic field and causing said oil-gauge strip variations to-aifect said magnetic field in time delayed relationship in accordance with such strip variations.

10. The method of handling material capable of being magnetically attracted which is first in strip and then in sheet form, comprising feeding a'strip of such material, continuously gauging such strip of material, causing off-gauge strip'variations to establish a time delayed electrical circuit, shearing the strip into sheets, conveying all such sheets within the influence of a magnetic field which is normally of sufficient strength to attract such sheets and causing the strength of such magnetic field to be temporarily ing such a strip, shearing it into sheets, conveying all such sheets within the influence of a magnetic field normally of suflicient strength to attract such sheets, and reducing the strength of such magnetic field from time to time as required to severance into sheets comprising determining to prevent the magnetic attraction of certain of such sheets, said last operation being under the control of variations in the material itself while .it is still in strip form and prior to shearing the metal is still in strip form for controlling said directing means.

13. An apparatus for classifying metal sheets into an "O. 'K." group and an off-gauge group as they are sheared from strip comprising means for feeding such strip, means for determining the thickness characteristics of such strip during the feeding operation, means for shearing the strip into sheets and means for magnetically conveying 0. K." sheets to a separate point of discharge from oil-gauge sheets.

14. In a classifying apparatus of the kind described, means for receiving sheets in a stream and for conveying them all in a common path, means for magnetically picking up certain of such sheets having predetermined thickness characteristics and for conveying them to a point of discharge and means for conveying the remainder of the sheets to a difi'erent point of discharge, said sheets .as received having been formed from strip upon which continuous gauging has been carried out before severance into such sheet".

15. In a classifying apparatus of the kind described, a first conveyor for receiving sheets as they are sheared from strip and for moving them in common path, a second conveyor associated with said first conveyor and adapted to pick up magnetically certain of the sheets from said first conveyor and to discharge them to a third conveyor, a third conveyor which receives the sheets magnetically selected by the second conveyor and delivers them to a point of discharge and a fourth conveyor associated with said first conveyor adapted to receive the unselectedbalance of the sheets from the first conveyor and to deliver such sheets to a separate point of discharge.

16. An apparatus for classifying metal sheets as they are sheared from strip and in accordance with their strip gauge characteristics prior to shearing comprising means for continuously determining the gauge characteristics of the strip, means for severing the strip into sheets of substantially equal lengths, means for conveying all the severed sheets to a common point or zone, means under both automatic and manual control for magnetically selecting only those sheets which are to form a single classification of sheets, means for conveying such selected sheets in a different path of travel from unselected sheets and means for forming each classification of sheets into a separate stack or pile at a separate point.

17. An apparatus for classifying metal sheets into 0. K. thickness sheets and off-gauge sheets without performing any characteristicdetermining operations upon the sheets themselves which comprises means for determining the thickness characteristics of a metal strip, means for shearing the strip into sheets of substantially equal lengths, means for conveying all the sheets to a common point or zone and means at such point or zone for determining the path of travel of each individual sheet, said means comprising a magnetic conveyor which, under control in accordance with the strip determined characteristics, magnetically diverts from the sheets only those sheets which are to form a single classification.

18. An apparatus for classifying metal sheets into 0. K. sheets and off-gauge sheets in accordance with the characteristics of such material as determined while still in the form of strip comprising means for determining classification controlling characteristics of the strip, means for shearing the strip into sheets of substantially equal lengths, means for conveying all the sheets to a common point or zone and .means at said point or zone for dividing the sheets into two paths of travel in accordance with their strip determined characteristics, said means including a magnetic conveyor provided with a plurality of magnetic coil-core unitshaving the capacity of setting up a magnetic field of sufllcient strength to cause the "O. K. sheets to pass to said magnetic conveyorand thus transferring them to conveying means which discharges them at a separate point, means for predeterminedly piling the O. K. sheets at such point, and means for piling off-gauge sheets at a separate point.

19. An apparatus for classifying metal sheets into two groups whereof one group has predetermined thickness characteristics comprising.

means for determining the thickness characteristics of a strip of metal prior to its severance into sheets, meansfor severing the strip without stopping it into sheets of substantially equal lengths,

means for conveying all the sheets to a common,

sheets to a separate point of discharge.

20. An apparatus of the kind described comprising a plurality of conveyors defining two possible paths of travel therethrough, means for operating said conveyors in a controlled relationship, means for determining the thickness characteristics of a strip of metal the 'sheetssubsequently sheared from which are to be classified by said system of conveyors, means forshearing the strip into sheets of substantially equal lengths, and means for conveying such sheets to said conveyor system in such manner that "0. K. sheets are caused to follow one of the paths of travel therethrough and oft-gauge sheets are caused to follow the other path of travel therethrough, and means for piling sheets discharged at theend of each such path of travel.

21. An apparatus for handling material capable of being magnetically attracted and which is first in strip and then in sheet form which comprises means for feeding such a strip of material, means for determining the gauge characteristics of the strip, means for causing-off-gauge strip variations beyond predetermined tolerance limits to be impressed upon an electrical circuit, means for shearing such strip into sheets, means for conveying all such sheets within the influence. of a magnetic field normally of sufficient strength to attract such sheets and means actuated and controlled by said gauge determining means and hence by said electrical circuit for temporarily reducing the strength of such magnetic field to a value insuflicient to attract sheets.

22. An apparatus for handling material capable of being magnetically attracted and which is first tract such sheets and means actuated and con- 'trolled by said gauge determining means and hence by said electrical circuit for temporarily reducing the strength of such magnetic field'to a value insuflicient to attract sheets, saidlast means including magnetic coils electrically segre gated into groups and electro-magnetic devices for de-energizing one group of such electrically segregated coils. v

23. An apparatus for handling material which is capable of being magnetically attracted which is first in strip and then in sheet form which comprises means for feeding a strip of such material, means for continuously determining the gauge characteristics thereof, means for shearing such strip into sheets of substantially equal length, means for conveying all such sheets into a magnetic field normally of suii'icient strength to at-- tract such sheets, a plurality of magnetic coilselectrically segregated into at least two groups for setting up such magnetic held and means for de-energizing one such group of electrically segregated magnetic coils in response to said gauge de-' termining means to, reduce the strength or the magnetic field to a value insumcient to attract sheets, variations beyond predetermined tolerance limits in such-material while still in strip form' actuating and controlling said de-energization and means for conveying magnetically attracted sheets to a point oi discharge diflerent from that of unattracted sheets.

24. In an apparatus of the kind described, a

magnetic conveyor provided with a plurality orthe magnetic attraction of the remainder of said sheets. p 25.1nan'apparatus of the kind described, magnetic conveyor provided with a plurality of stationary magnetic coils located within a belt traveling therearound, connections for electrically segregating said magnetic coils into at least two groups and connections for energizing such groups and for de-energizing one of said groups, means for conveying sheets "as they are sheared from "strip within the magnetic field set up by said coils, means for magnetically attracting certain only oi such sheets and means for preventing the magnetic attraction or the remainder of said sheets, means for continuously gauging such material 'whileit is still in strip form and prio to being sheared into sheets and connections oetween said gauge and one 01. said groups oicoils whereby variations in said strip beyond predetermined tolerance limits causes the de-energization aforesaid.

HOWARD B. CUMMINGS. GEORGE R. CARROLL. 

